Etching machine



June 4, 1929.

A. HoLMsTRoM 1,716,270

ETCHING MACHINE Filed March l, 1928 3 Sheets-Sheet l 4Z y V640/ June 4, 1929. A HOLMSTROM l 1,716,270

ETCHING MACHINE Filed March l, 1928 3 Sheets-Sheet 2 Jun; 4, 1929.

A. HOLMSTROM ETCHING MACHINE Filed March 1, .1928

s snets-sheet 5 Patented June 4, 1929.

NETE@ STATES AXEL HOLMSTROM, OF MONTE CARLO, MONACO.

ETGHING MACHINE.

Application nled March 1, 1928, ,Serial No. 258,237, and in Germany October 6, 1927.l

My invention relates to the rotor type of etching machines in which a rotating blade casts a spray of etching liquor over one side of a plate or plates to be etched.

A purpose of my invention is to increase the capacity of a, rotary type of etching machine by adapting it to operate simultaneously upon a number of plat-es. I support the plates to be etched back of and above a rotating impeller as w .ll as in front of the impeller. Hitherto the plates have been placed in front only of the inipeller.

A further purpose is to provide a novel form of plate holder at the top of an etching chamber, a holder adapted to support the force of the upwardly flung spray, and adapted to easy plate insertion and to easy adjustment to different widths of plate. I support one side of the plate in a horizontal lll-groove that is optionally along the front wall of the chambre' or along what is in effect an inwardly directed ledge from the front wall, and support the other side of the plate along a groove in a member that has rounded ends resting upon ledges and has a wide offsetting portion overlapping and resting on the plate, supporting the pla-te from any upward movement duc to the impact of the upwardly flung spray.

A further purpose is to support the end bearings of the rotor member of an etching machine upon brackets integral with the etehin g chamber.

A further purpose is to seat an etching chamber inan auxiliary outsi de tray reservoir of etching liquor and provide circulation between the liquid in the etching chamber and that in the outside reservoir. I thus greatly diminish the turbulence of theliquor beneath the rotating blades, also make the periods between replacements of the etching liquor longer in that the effective charges of the liquor are larger and the tray catches and returns to circulation any etching liquor spilled upon the outside walls of the chamber. I may seat a plurality of etching` chambers along side of one another in and along the same tray reservoir.

Further purposeswill appear in the specification and in the claims.

I have elected to show one form only of my invention, selecting a forml that is practical and efficient in operation and which illustrates particularly well the principles involved.

Figure 1 is a longitudinal vertical section of a structure embodying my invention.

upon the ing chambers are seated in a single tray reserf voir at the bottom.

Like numerals refer to like partsin all Figures.

Describing in illustration and not in limitation and referring to the drawings:

The structure illustrated comprises anetching chamber 10 of acid resistant material,l preferably stone-ware, that is seated within a tray reservoir v11 also preferably stone-ware.

T he tray presents upwardly directed ledges 12 and 13 alongopposite sides andthe opposite ends of the etching chamber rest upon these ledges so that there is a reservoir space 1li between the t-ray and the bottom 0f the chamber, except at the supported ends resting on the ledge.

The tray makesl fairly close lit4 with the walls of the ends 15 and 16 and of the forward side 17 of the etching chamber, but'desirably extends rearwardly at 18 somewhat beyond the chamber.

The tray reservoir is provided with suitable drainage opening- 19 and its upper edges are chamfered at 20 to insure drainage inwardly of any liquor running down the outsideI of the etching chamber.

The rotor 21 which casts the spray of etching liquor on to the Vplates tobe etched, is placed further inwardly from the rear side 22 of the chamber than has been customary in the past, and I provide a spray battle 23 along the rear side of the rotor that cooperates with the blades 24C of the rotor to direct spray.

The baffle 23 is formed to properly direct the spray and hasits opposite ends supported in rectangular pockets 2 5 on the interior.

It should be of acid resistant material and preferably stone-ware.

I provide along the upper edge of the baffle a groove 26 that forms a seat for plates 27 above the battle and on the rearwardside of the rotor. In the past'etching plates have been placed on the forward side of the chamber but not so far as I know upon the rearward side. Instead of plate 27 a sheet of plain or other contour can be used to act as a secondary baille combining with the baffle to break up and redistribute the spray and return the acidto the paddles.

The forward side 17 of the chamber is provided with a usual seat 28 to receive a plate v29 etching in front of the rotor, and there is also provision for seating a plate or plates 30 above the rotor.

A plate 30 supported above the rotor is subjected to the varying impact of the blast of spray from the rotor and has to be firmly supported along both edges against upward movement.

The forward edge of the upper plate is supported in a horizontal groove 31 alone the front wall of the chamber or optionally in a groove 32 along the inner et ofv a stoneware removable shelf 33.

Opposite ends of the shelf 33 are supported upon ledge abut-ments 34 and 35 along` Vthe opposite ends of the chamber. These abutments are preferably of equal height and sloped upwardly from front to rear. 4

'Ihe forward portions of the ledges seat opposite ends of the shelf member 353 which is used to permit supporting the plate 3() more directly above the rotor to be better in the path of the spray than would be the case if it were not used.

Vhen etching abnormally wide plates the shelf member is removed.

At the inner edge of the shelf 33 I locate a plate member 36, which has ends fitting into oppositely directed groovedl brackets 37 on the end walls of the chamber and which protects the adjoining upper edge of the wall and cover from spray.

yIVhen the shelf is removed the plate member 36 which is suitably glass rests upon. the eaching plate, supporting the etching plate from rattling when subjected to the Varying impact of the spray.

The rearwaid edge of the plate 30 is supported in the groove 88 of a holding member 39,

The holder 39 has a hook-like sect-ion and roller extensions 40 at the ends which rest on the sloping ledges 34 and It extends forwardly at 41 intermediate the ledges so as to overhang and rest upon the plate 30 some distance inwardly from the groove' 3S. The overhanging portion tends to swing down and is prevented from swinging` downwardly by resting upon the plate. It thus firmly clamps the plate from upward movement, the weight of the holding member being sufficient to avoid danger of bodily lifting of the holding member and plate under the force of the spray from the rotorn The holding member 39 is shown with a handle 42 and is adapted to be slid by hand to any position along the opposing ledges 34 and 35 in order to accommodate different widths of plate. It is desirably made of stone-ware.

I sho-w the chamber provided with a usual removable cover 4S, and with. exhaust flue 44 to afford exhaust from the chamber for the poisonous fumes. Pressure and air intake openings 45 are also shown.

Conduit connection is provided between the etching chamber and tray reservoir at openings 4G along` th-e rear yand toward the front at openings 47.

These openings in the rear wall and bottom of the chamber' insure a rapid circulation between the liquor inthe chamber and that in the reservoir during the operation of the rotor.

The opening 48 between the rear wall of the chamber and that of the tray may be desirably covered with a board or other closure. V Y

The shaft of the rotor is protected in the usual way from contact with the etching liquor and its ends extend through the openings 49 in the end walls of the chamber, these openings being protected by interfitting annularly grooved bosses 50 around the openings and cooperating mushroom sleeves 51 on the shaft. The ring grooves 52 receive the outwardly directed flanges 53 and are open at 54 and 55 for drainage so that any liquor working up the slope of the flange 53 of one of the sleeves which rotates with the' shaft, comes olf into the groove and drains back down through the openings 54 and 55 intothe acid of the reservoir.

The ends of the shaft after extending through the walls of the chamber are supported in suitable roller bearings 56 and one of the features of my invention is directed to the mounting of these bearings.

I support the bearings upon brackets 57 integral with the end walls'of the chamber, preferably with suitable cushioning 58 between the bearings and the brackets.

As illustrated the bracket 57 is of inverted l) section perforated at 50 above the bearing.

'Ihe bearing is carried in a casing 60 which in turn is held to place by a downwardly extending bolt 61 which passes through the perforation in the bracket. The cushioning washer 62 and metal washer 68 support the head 64 above the bracket and the cushioning insures against danger of undue vibration between the chamber and rotor element.

The shaft is extended at onevend beyond its bearing for driving purposes, being driven in any suitable way not shown.

lVhen several etching machines are to be used side by side I may set two or more of them in a single tray reservoiras illustrated diagrammatically in Figure 7.

The etching machine is open at the bottom and separate tray supports forthe machine 'may be employed. Using the tray to hold etching fluid for the machine has much advantage even when there is but a single etching machine supported upon the tray; and still greater advantage where more than a single machine is to be supported from the same tray. In both cases the tray aliords a cooling tank for the etching liquor away from the heat of the etching process, giving a very much larger cooling surface than would otherwise be secured. The mere fact that the bath is larger would assist in this also.

The fact that a part of the bath is outside of the etching chamber gives opportunity for foreign mattei' to settle out of the bath which would not be possible where the bath was wholly subject to the violent agitation present inside of the etchingchamber.

lllhere there are a number of machines for the same bath not all of the machines will be in operation at the sametime using the capacity for cooling of any machine which is not operating to assist in cooling the bath for the benefit of the other machines.

W'hcre the character of work is variant and it is desirable to use a smaller bath with one type of work than with another the separability of the machine from the bath tray permits substitution of different traysl or tanks having diiferent bath capacities desired.

In view of my invention and disclosure variations and modifications to meet individual whim or particular need will doubtless become evident to others skilled in the art, to obtain all or part ofthe benefits of my invention without copying the structure shown,rand I, therefore, claim all suoli in `so far as they fall within the reasonable spirit and scope of my invention.

Having thus described my invention what I claim as new and desire to secure by Letters Patent is 1. In an etching machine, a box, a horizontal rotatable paddle therein adapted to cast etching liquor upwardly and plate-supporting means near the top of the box comprising a stationary member grooved along a rearward side and adapted to receive one side of a plate in its groove and a plate-holding movable member rearwardly spaced from the first having pivotal support at the ends upon the box and in holding position receiving the other side of the plate in a forwardly directed groove, and overlappingthe plate so that the plate prevents it from swinging downwardly and its weight supports the plate from moving upwardly.

2. In an etching machine, an etching chamber, a rotatable paddle therein adapted to cast etching liquor upwardly, and a support for holding a plate vertically above the paddle, comprising a structure along the front of the chamber presenting a rearwardly directed groove seat to the forward side of a plate,

ledges along opposite ends of the chamber, a holding member along the back of the plate seating' the rearward side of the plate in a groove and extending forwardly above the` plate so as to have its center of gravity above the plate forwardly of the groove, and end extensions from the member pivotally supporting the member upon vthe ledges rearwardly of its center of gravity.

In an etching machine, an etching chamber, a rotatable paddle therein adapted to cast etching liquor upwardly, rearwardly and infront of the chamber near the top, rearwardly7 and upwardly sloping ledges along opposite ends of the chamber, a plate supporting member along' the back of the plate presenting a forwardly directed groove seat'to the rear edge of the plate and forwardly overlapping the plate so as to have its center of gravity forwardly of the rear edge of the plate, and end extensions from the'member pivotally supported upon the ledges and axially rearwardly of the center of gra fity of the plate.

4t. In an etching machine, an etching chamber, a rotatable paddle adapted to cast etching liquid upwardly within the chamber', means for holding one edge of the plate so that the plate will lie in nearly horizontal position at a higher level than the paddle and means for holding the opposite edge of the plate comprising a pivoted member supporting the edge ofthe plate and overhanging the plate to rest upon it and holdthe plate down.

5. In an etching machine, an etching chamber, a horizontal rotatable paddle therein adapted to cast etching liquor, and a spray baille along the rearward side of the paddle adapted to direct the cast liquor in cooperation with the paddle and having a groove seat along its upper side to support the lower edge of a plate to be etched at the rearward side of the paddle.

G. In an etching` machine, an etching cham-` ber, a horizontal rotatable paddle therein adapted to cast etching liquor, and a spray baffle along the rearward side of the paddle, removably supported at its ends and adapted to direct the cast liquor in cooperation with the paddle.

7. In an etching machine, an etching chamber, a horizontal rotatable paddle therein adapted to cast etching liquor, and a spray baffle along the rearward side of the paddle, removably supported at its ends, adapted to direct the cast liquor in cooperation with the paddle and having a groove seat along its upper side to supportthe lower edge of a plate tobe etched at the rearward side of the paddle.

8. In an etching machine, an etching chamber, a rotatable paddle therein adapted to cast etching liquor upon the plates to be etched, a shaft carrying the paddle extendvwardly directed groove abutments along the ing through the end walls of the chamber, a bracket integral with and outside of the etching chamber and a bearing resiliently supported upon the bracket and supporting one end of the shaft.

9. In an etching machine, an etching chamber, a rotatable paddle therein adapted to cast etching liquor upon plates to be etched, a shaflt carrying` the paddle extending through the end walls of the chamber, a bracket integral with and outside of the etching chamber at each end of the. shaft and a depending beaiing supported from the bracket and supporting one end of the shaft.

10. In an etching machine, an etching chamber, a .rotatable paddle therein adapted to cast etching liquor upon plates to be etched, a shaft carrying the paddle extending through the end walls of the chamber, a bracket integral with and outside o'lf the etching chamber having a perforation directed toward the shaft, a bearing supported upon the bracket through the perforation and supporting one end ot the shaft, and a cushion between the bearing and the bracket.

ll. In an etching machine, a stone-ware etching chamber, a rotatable paddle therein adapted to throw etching liquor, a shaft carrying the paddle extending through an opening in an end wall of the chamber, an inverted U downwardly flaring bracket integral with the chamber over the extended end of the shaft and downwardly perforated toward the shaft, a bearing member supporting the extended end and having an upwardly extending supporting rod through the perforation in the bracket, and a cushion between the bracket and the bearing member. 12. In an etching machine, an etching chamber containing a rotary paddle adapted to cast etching liquor over plates to be etched supported inside the chamber and having a bottom opening in combination with a tray reservoir seating the chamber and having anupwardly outward chamfer from the out side of the chamber so as to catch any liquor running down the outside of the chamber.

13. In an etching machine, an etching chamber, a horizontal rotary paddle therein near the bottom thereof, a baffle along and adjacent to the paddle from end to end of the chamber and adapted to cooperate with the paddle in directing the etching liquor thrown by the paddle, a tray reservoir surrounding the bottom of the chamber and having ledges along opposite sides seating the etching chamber, and conduit connec-A tions between the reservoir and chamber below the paddle andupon opposite sides of the baffle.

14. A tray reservoir for etching liquor, a plurality of etching units in and along the tray, each including spraying means and a chamber, each opening into the tray and means supporting the units above the bottom ol the tray.

l5. A battery oit etching machines coinprising a plurality of etching chambers open at the bottom, etching plate supports and spray mechanism in the chambers and a tray :for etching fluid supply common to, supplying and supporting all of the chambers'.

16. A battery of etching machines comprising a plurality of etching units open at the bottom, etching plate supports and spray mechanism for the units and a tray :tor etching fluid supply common to all of the units whereby uniform etching fluid conditions may be maintained 'for the battery.

AXEL HOLMSTROM. 

